Rectangular duct

ABSTRACT

Longitudinal rectangular ducting 20 for use in HVAC systems is composed of a longitudinal top wall 22 of a desired length and constructed from thin gauge material, for example, from coil stock. The ducting 20 includes a mirror image bottom wall 24 which can be constructed similarly or identically to the top wall 22. The ducting 20 further includes side walls 26 and 28 vertically spanning the outer edge portions of the top and bottom walls 22 and 24. The top, bottom and side walls all having longitudinal edge portions. The longitudinal side edge portions of the first and second wall members deformed to define a standing pocket seam for receiving the side edge portions of the third and/or fourth longitudinal members therein.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 62/839,386, filed Apr. 26, 2019, the entire contents of which are incorporated herein by reference.

BACKGROUND

The present invention pertains to square and rectangular heating, ventilating and air conditioning (HVAC) ducting and methods for making such ducting. Square and rectangular ducting are widely used in HVAC systems. Such ducting can be located between floor or ceiling joists, whereas ducting of other cross-sectional shapes, such as round, may not fit in such locations and still be sufficiently large enough to handle the HVAC load required.

Referring to FIGS. 1 and 2, it is known to manufacturer square and rectangular ducting structures, such as structure 200, by bending a sheet of thin gauge material to form the corners and the four walls of a length of ducting 202 and then join the walls together along one corner 204 to form an integral structure. This corner joint may take various forms, such as by overlapping portions of the ducting and then screwing the overlapped portions together, or by utilizing and “S” shaped flange 206 or other shaped member to join the ducting along corner 204.

Typically, lengths of square and rectangular ducting produced in this manner are relatively limited in length due to the size of the brake press or other machinery used to form the corners of the ducting, and also limited by the length of the sheet metal stock available.

Because square and rectangular cross-section HVAC ducting is typically of relatively short lengths, it is necessary to connect ducting sections end-to-end to achieve a desired overall length. In this regard, as shown in FIG. 1, a face flange structure 208 is integrally formed at the ends of each wall of the duct 202. The face flange structure has a mating or face section 210 extending perpendicularly to the corresponding wall of the duct 202 and a reinforcing hem structure 212 extending transversely from the distal edge of the flange face 210. The hem structure 212 may be folded over on itself to form a double thick section for additional strength. In FIGS. 1 and 2, the hem section 212 is folded inwardly on itself. The opposing face flanges 208 of adjacent duct lengths 202 are clamped together with clips 214 that grip or encircle the hem structures 212, as shown in FIG. 2.

It will be appreciated that the prior art ducting structure shown in FIGS. 1 and 2 is time-consuming and expensive not only to fabricate, but also assemble and install in the field. The present disclosure seeks to provide a new rectangular and square HVAC ducting construction, as well as more economical and faster methods for manufacturing, assembling and installing HVAC ducting of rectangular and square cross section.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a pictorial view of a prior art rectangular duct structure;

FIG. 2 is a fragmentary view of corner portions of the prior art duct structure of FIG. 1;

FIG. 3 is a pictorial view of a rectangular duct structure in accordance with the present disclosure;

FIG. 4 is a fragmentary view of a portion of the duct structure of FIG. 3 as partially assembled with standing seam pockets extending outwardly (upwardly) from the outer surface of a wall section of the ducting;

FIG. 5 is a view similar to FIG. 4 with the duct structure further assembled;

FIG. 6 shows end views of lengths of thin gauge coil stock used to manufacture the duct structure of FIG. 3;

FIG. 7 is an end view of the top and bottom wall segments of the duct structure of FIG. 3 wherein standing seam pockets have been formed therein to extend outwardly (upwardly) from the outer surface of the wall segments;

FIG. 8 is an end view of the duct structure of FIG. 3 wherein side walls of the duct structure have been engaged within the standing seam pockets of the top and bottom walls of the duct structure of FIG. 3;

FIG. 9 is an end view of FIG. 8 wherein the standing seam pockets have been closed over the upper and lower edges of the sidewalls;

FIG. 10 is an end view corresponding to FIG. 9 wherein the closed standing seams have been rotated laterally to overlap the sidewalls of the duct structure;

FIG. 11 is an end view corresponding to FIG. 9 wherein the standing seams have been rotated laterally to overlap the other surfaces of the upper and lower walls;

FIGS. 12A and 12B illustrate draw forming the standing seam pockets in the side edges of the top and bottom walls of the duct structure;

FIGS. 13A and 13B illustrate a process of roll forming the standing seam pockets into the marginal side edges of the top and bottom duct walls;

FIG. 14 illustrates a process of closing the standing seam pockets once the upper and lower edges of the sidewalls have been engaged therein;

FIG. 15 is an end view of an alternative embodiment of the present disclosure composed of two identical duct structures each forming a sidewall and one of the top or bottom walls of the duct structure and having a singular standing seam pocket formed therein for receiving the distal edge of the sidewall of the corresponding duct structure;

FIG. 16 is an end view similar to FIG. 15 but with the standing seam pocket crimped or otherwise closed with distal the edge portion of the corresponding sidewall of the duct structure engaged therein;

FIG. 17 is a view similar to FIG. 16 but where the closed standing seam pockets have been turned or rotated laterally to overlie the sidewalls of the duct structure;

and

FIG. 18 is a view similar to FIG. 17 but with the standing seam pockets turned or rolled laterally over to overlie the top and bottom walls of the duct structure.

DETAILED DESCRIPTION

Referring to FIGS. 3-5, rectangular ducting 20 constructed in accordance with one example of the present disclosure is illustrated for use in HVAC systems. The ducting 20 is composed of a longitudinal top wall 22 of a desired length and constructed from thin gauge material, for example, from coil stock. The ducting 20 includes a mirror image bottom wall 24 which can be constructed similarly or identically to the top wall 22. The ducting 20 further includes side walls 26 and 28 vertically spanning the outer edge portions of the top and bottom walls 22 and 24. The side walls 26 and 28 can also be formed from thin gauged coil stock of a desired length. Standing pocket seams 30 are formed along each side edge of the top wall 22 and bottom wall 24. See FIG. 4. The standing pocket seams are designed to receive therein the adjacent top and bottom edges of the side walls 26 and 28 thereby to cooperatively form with the top and bottom walls 22 and 24 HVAC ducting of rectangular or square interior cross-sectional shape. The standing pocket seams 30 are crimped or otherwise closed, as depicted by arrows 31, to capture and retain the edges of the side walls 26, 28 there between. Also, once the side edges of the side walls 26, 28 are captured or sealed within the pocket seams 30, the pocket seams can be rolled in the left or right direction over to form a sealed, secure connection or joint overlying the sidewalls 26 and 27 or overlying the top and bottom walls 22 and 24. See arrows 31A and 31B in FIG. 5 and see FIGS. 10 and 11.

To discuss the foregoing in more detail, the initially formed standing pocket seams 30 extend outwardly, for example, upwardly, from the exterior of the top wall 22 and outwardly (for example, downwardly) from the bottom wall 24, see FIG. 8. The nominal pocket seams 30 define lead-in or opening 32 for receiving therein the upper and lower edges 34 and 36 of the side walls 26 and 28. Such edges 34 and 36 bear against or near the base or bottom 23 of the standing pocket seams 30. The standing pocket seams are crimped or otherwise closed to capture the edges 34 and 36 of the side walls within the standing pocket seams, See FIG. 9. Such closure of the standing pocket seams 30 is sufficient to produce a rigid square or rectangular HVAC duct in compliance with applicable industry standards as well as building codes.

In addition to or in lieu of crimping or otherwise closing the standing pocket seams 30 so as to extend upwardly and downwardly from the top and bottom walls 22 and 24, the standing pocket seams, with the side wall edges 34 and 36 therein, may be turned or rolled over to overlap the exterior of the side walls 26 or 28 (See FIG. 10) or the exterior of the top and bottom walls 22 and 24 (See FIG. 11). As will be appreciated, this operation not only increases the structure rigidity and integrity of the ducting 20, but also can enhance the integrity of the joint created between the standing pocket seam 30 and the side wall edges 34 and 36.

Ducting 20 can be attached end to end by use of various types of connectors, including flanged connectors as described and illustrated in U.S. Pat. No. 7,104,104, specifically incorporated by reference herein. Alternatively, standard seam connectors may be utilized to interconnect adjacent ducting 20, as disclosed in U.S. Pat. No. 9,101,969, specifically incorporated herein.

A band 40 can be used to tightly encircle the exterior of the ducting 20 at one or more locations intermediate the ends of the ducting. The band 40 serves to assist in the ducting retaining its shape without the outward bulging of the walls 22, 24, 26 or 28. As will be appreciated, the band 40 could be composed of strap material used to encircle the ducting 20 with the ends of the strap material fastened together by a threaded connectors or other standard means. Wire, wire rope, cabling, or other similar material may also be used to form the band 40. The ends of the wire type material may be securely twisted or otherwise attached together using standard portable or other equipment.

It will be appreciated that for rectangular ducting, the sides of the ducting that have a greater span, whether across the top and bottom of the ducting or along the height of the ducting, can be composed of a material of a thicker gauge than that of the other shorter sides of the ducting thereby to “even out” the resistance of the ducting to deformation, for example, outward bulging due to the air pressure within the ducting. This is made possible because the top and bottom walls begin as individual wall members in the form of lengths of coil material, and the side walls 26 and 28 also begin as individual wall members in the form of lengths of coil material.

Although not shown, thermal or acoustical insulation material may be applied to the inside surfaces of the top, bottom and side walls 22, 24, 26 and 28 prior to assembly of the walls to form the ducting 20. Such insulation material may be adhered to the inside surfaces of the top, bottom and side walls. Alternatively, or in addition, the insulation may be mechanically fastened to the top, bottom and side walls by screws or bolts engaged with enlarged washers that press against the insulation material facing the interior of the duct 20 so as to more widely distribute the load of the mechanical fastener on the insulation material.

Next, FIGS. 6-11 illustrate one manner of forming and assembling the ducting 20 in accordance with the present disclosure. Initially, the top and bottom walls 22 and 24 and side walls 26 and 28 are cut to length from coil or roll stock of a desired width. It can be appreciated that the length of the cut stock can vary as desired and can be many multiples in length relative to the lengths of square or rectangular HVAC ducting made by the traditional methods described above. For example, the lengths of the top and bottom and side walls can be up to ten or twenty or thirty feet in length or even longer, especially if the ducting 20 is fabricated at the job side.

Next, the standing pocket seams 30 are formed in the top and bottom walls 22 and 24. Such pocket seams, as described below, can be formed by various roll-forming techniques, as well as by draw forming or bending techniques. Also, the nominal cross section of the pocket seam can be of various configurations, such as in the form of a right triangle, a V-shape, a U-shape, or other shape that defines an open mouth 32 for receiving the edges of the side walls, and a closed “bottom” 33 for bearing against the edges of the side wall.

As shown in FIG. 8, the side walls 26 and 28 are next engaged within the standing seam pockets 30 and then the pockets are crimped or otherwise closed as shown in FIG. 9 to capture the top and bottom edges of the side walls 26 and 28 within the pockets. This results in the sturdy, airtight rectangular shaped HVAC ducting wherein the standing pocket seams extend outwardly of the ducting, for example, upwardly and downwardly as shown in FIG. 9. Typically the standing seams may extend from about 1 inch to about 6 inches above or below the outer surfaces of the top and bottom walls 22 and 26. The interior of the ducting is smooth without any seams or other discontinuities therein to disrupt the air flow.

Referring to FIG. 10, the upwardly and downwardly standing pocket seams can be folded over to overlie the side walls 26 and 28, or as shown in FIG. 10 folded over to overlie the top and bottom walls 22 and 24 as shown in FIG. 11, using a standard rolling or other process.

The standing pocket seams 30 can be formed by numerous techniques. For example, as shown in FIGS. 12A and 12B, the standing pocket seam 30 can be produced in a draw die composed of a female die member 50 having a V-shaped depression 52 therein corresponding to the desired shape of the standing pocket seam. A male die member 54 has a protruding V-shaped leading section 56 matching the shape of cavity 52 so that when the male die is pressed downwardly into the female die, the standing pocket seam 30 is formed along a side edge of the top wall 22 or bottom wall 24. The standing pocket seam 30 along the opposite side edge of the top wall may be formed in the same manner, for instance, by moving the top wall 22 laterally so that the opposite side edge is in registry with the V-shaped shaped cavity 52.

Another method for forming the standing pocket seams 30 is illustrated in FIGS. 13A and 13B. As shown in FIG. 13A, the edge portions of the top and bottom walls 22 and 24 are fed between a female and male roller die set 70 and 72 that rotate about respective axes 74 and 76 via axles 78 and 80. The female roller die is constructed with a V-shaped groove 82 of a shape that is desired for the standing pocket seam 30. The male roller die 72 likewise includes a V-shaped circumferential portion 84 projecting from the base of the roller to engage within the V-shaped groove 82. The rotating rollers 70 and 72 move progressively towards each other so the V-shaped circumference 84 engages into the V-shaped groove 82 thereby causing the pocket seam 30 to be formed as the top and bottom walls 22 and 24 pass between the roller set thereby to form the standing pocket seam 30 along each side of the top and bottom walls.

Once the standing pocket seams 30 are formed and the edges of side walls 26 and 28 disposed within the standing pocket seams, the standing pocket seams can be crimped or closed by numerous techniques. For example, the pocket seam can be closed by passing the standing pocket seams side-by-side with the side wall edges engaged therein, through a series of pinching roller sets 90A-90E consisting of rollers that are positioned progressively closer to each other. The roller sets are powered to rotate so as to urge or force the standing pocket seams 30 there through while progressively closing or pinching the pocket seams so as to capture the edges of the side walls 26 and 28 within the standing pocket seams.

Other techniques also can be utilized to close or pinch the pocket seams, for instance by using a punch to press against the standing pocket seam.

FIGS. 15, 16, 17, and 18 disclose a further embodiment of the present disclosure wherein ducting 100 is composed of two identical sections or structures 102, each which are angle shaped in cross section to form one sidewall and either the top wall or the bottom wall of the duct. A singular standing pocket seam 104 is formed along one edge portion of the structure 102 so as to receive therein the undeformed edge portion of the other structure 102 of the ducting 100. Thereafter, the pocket seam 104 is crimped or otherwise closed so as to secure the edge 106 of the other duct structure 102 therein.

Once the standing pocket seam 104 has been closed, the pocket seam, with the edge portion 104 of the opposite duct structure 102 therein, may be turned laterally over to overlap the exterior side walls of the duct 102, as shown in FIG. 17, or to overlap the top and bottom walls of the duct section 102 as shown in FIG. 18.

As will be appreciated, the ducting 100 can be produced using techniques the same or similar to that used to produce ducting 20. However, only one standing pocket seam is required per duct section 102. Once the pocket seam 104 has been formed in section 102, the section 102 can be bent to form corner 106 in a standard manner resulting in a side wall and in the top or bottom wall of the ducting 100. Further, the pocket seam 104, within adjacent edge portion of the opposite duct section 102 therein, can be closed using a set of pinching rollers, such as pinching roller set 84 shown in FIG. 14.

It will be appreciated that the ducting 100 shown in FIGS. 16-18 requires fewer fabrication steps than ducting 20. However, there may be limitations as to the maximum cross-sectional size of ducting 100 given that there is a limit to the width that coiled or rolled sheet metal is manufactured. Further, the greater the width of the sheet metal coil the more expensive the sheet metal on a per-area basis. In certain situations, it may be more economical to utilize narrower width sheet metal to form ducting from four separate walls as described above. Nonetheless, the ducting 100 also has the advantage of being able to be manufactured in significant lengths thereby reducing the number of connections required in a ducting system. As a result, the cost of manufacturing the ducting system is lessened as well as the cost of installing the ducting system at the job site.

While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. 

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
 1. Longitudinal HVAC ducting of rectangular or square interior cross section, comprising: first and second longitudinal wall members in spaced parallel relationship to each other, the first and second wall members having longitudinal side edge portions extending there along; third and fourth longitudinal wall members in spaced parallel relationship to each other and disposed transversely to the first and second wall members, the third and fourth wall members having side edge portions engaged with the side edge portions of the first and second wall members to cooperatively form HVAC ducting of a rectangular or square interior cross-section shape; and the longitudinal side edge portions of the first and second wall members deformed to define a standing pocket seam for receiving the side edge portions of the third and/or fourth longitudinal members therein, the standing pocket seams extending outwardly of the rectangular or square cross-sectional interior ducting shape defined by the first, second, third, and fourth wall members.
 2. The longitudinal HVAC ducting of claim 1, wherein the standing pocket seams comprises the side edge portions of the first and second wall members doubled over on itself.
 3. The longitudinal HVAC ducting of claim 2, wherein: the first and second wall members have outer surfaces; and the standing pocket seams extend outwardly of the exterior surfaces of the first and second wall members.
 4. The longitudinal HVAC ducting according to claim 3, wherein the standing pocket seams of the first and second wall members extend transversely to the outer surfaces of the first and second wall members.
 5. The longitudinal HVAC ducting according to claim 4, wherein: the standing pocket seams define a height extending from the outer surfaces of the first and second wall members; and the standing pocket seams are deformed in a direction laterally to the height of the standing pocket seams.
 6. The longitudinal HVAC ducting according to claim 3, wherein: the standing pocket seams define a height extending from the outer surfaces of the first and second wall members; and the standing pocket seams, with the edge portions of the third and fourth wall members disposed therein, are deformed in a direction laterally to the height of the standing pocket seams.
 7. The longitudinal HVAC ducting according to claim 6, wherein the standing pocket seams are deformed laterally to overlie the exterior of the first and second wall members.
 8. The longitudinal HVAC ducting according to claim 6, wherein the standing pocket seams are deformed to overlie the exterior of the third and fourth wall members.
 9. A method of forming longitudinal HVAC ducting of a square or rectangular interior cross section, comprising: forming standing pocket seams along the side edges of first lengths of thin gauge metallic material, the standing pocket seams defining pocket openings leading into the standing seam pockets, and a closed standing seam pocket base; engaging the edges of second lengths of thin gauge metallic material into the standing seam pockets of a pair of the first lengths of metallic material through the pocket openings, the first pair of lengths of metallic material in opposing spaced relationship to each other and oriented so that the pocket openings can receive the edges of the second lengths of metallic material; and closing the openings of the standing pocket seams against the edges of the second lengths of metallic materials engaged within the standing seam pockets to trap the edges of the second lengths of metallic material within the standing steam pockets and thereby form longitudinal HVAC ducting in square or rectangular interior cross-sectional shape.
 10. The method of claim 9, further comprising forming the standing pocket seams by doubling over on itself the side edge portions of the first lengths of thin gauge metallic material.
 11. The method of claim 9, wherein forming the standing pocket seams to extend outwardly from the exterior surfaces of the first lengths of thin gauge metallic material.
 12. The method of claim 11, comprising forming the standing pocket seams to extend transversely outwardly from the outer surfaces of the first lengths of thin gauge metallic material.
 13. The method of claim 9, further comprising deforming the pocket seams, with the edges of the second lengths of metallic material engaged therein, laterally to overlie either the first lengths of thin gauge metallic material or the second lengths of thin gauge metallic material.
 14. Longitudinal HVAC ducting of rectangular or square cross section, comprising first and second longitudinal wall structures, each wall structure comprising: first and second integral wall sections disposed transversely to each other from a corner to define edge portions extending along the margins of the first and second wall sections distal from the corner; and a standing pocket seam formed along the edge portion of one of the first and second wall sections, wherein the two wall structures are positioned so that the edge portion of one of the first and second wall sections of each wall structure engages within the standing pocket seam formed in the other of the first and second wall structures, whereby the engaged first and second wall structures cooperatively define HVAC ducting of rectangular or square cross section.
 15. The longitudinal HVAC ducting of claim 14, wherein the standing pocket seams comprises the edge portions of the first or second wall sections doubled over on itself.
 16. The longitudinal HVAC ducting of claim 15, wherein: the first and second wall structures have outer surfaces; and the standing pocket seams extend outwardly from the outer surfaces of the first and second wall structures.
 17. The longitudinal HVAC ducting of claim 16, wherein the standing pocket seams of the first and second wall structures extend transversely to the outer surfaces of the first and second wall structures.
 18. The longitudinal HVAC ducting according to claim 17, wherein: the standing pocket seams define a height extending from the outer surfaces of the first and second wall structures; and the standing pocket seams are deformed in a direction laterally to the height of the standing pocket seams.
 19. The longitudinal HVAC ducting according to claim 14, wherein: the standing pocket seams define a height extending from the outer surfaces of the first and second wall structures; and the standing pocket seams with the edge portions of the first and second wall section of the corresponding first and second wall structure disposed therein, are deformed in a direction laterally to the height of the standing pocket seams.
 20. The longitudinal HVAC ducting according to claim 19, wherein the standing pocket seams are deformed laterally to overlie the exterior of either the first or second wall structures. 